The excitation of Lg wave by underground nuclear explosions
地下核爆炸Lg波的激发机制

Near-Source scattering of explosion-generated Rg wave into S wave appears to be the primary contribution to the low-frequency Lg wave in underground nuclear explosions, this mechanism has been supported by analysis of regional data from several Yucca Flats, NTS explosions by Patton and Taylor (1995), who further indicated that the prominent low-frequency spectral null in Lg wave is due to Rg wave from a compensated linear vector dipole (CLVD) source. In this study, the mechanism of the excitation of Lg wave by explosions in layered earth structures of the East Kazakh test site is further analyzed by using theoretical seismograms, and the result shows that the Lg spectra indicate prominent nulls showing strong dependence on shot depth and in remarkably good agreement with those expected from Rg wave due to a CLVD source.